Video Experimental Relacionado

Updated: May 3, 2026

Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes

Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes

Published on: October 15, 2016

Determinantes de especificidad en la desfosforilación de fosfoinosítidos: estructura cristalina de un arquetipo de

Y Tsujishita¹, S Guo, L E Stolz

¹Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, , Bethesda, MD 20892, USA.

|May 12, 2001

Resumen

Las 5-fosfatasas de polifosfato de inositol son cruciales para las funciones celulares y están relacionadas con el síndrome de Lowe. El análisis estructural revela su mecanismo enzimático y el reconocimiento del sustrato, lo que ayuda a comprender la enfermedad y la especificidad de las enzimas.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Molecular Biología Molecular
Biología Estructural Biología estructural.

Sus antecedentes:

Las inositol polifosfato 5-fosfatasas regulan procesos celulares vitales como el tráfico de membranas y la señalización del calcio.
La disfunción de estas enzimas está implicada en enfermedades humanas, especialmente el síndrome de Lowe.

Objetivo del estudio:

Para aclarar la base estructural de la actividad de la inositol polifosfato 5-fosfatasa.
Comprender los mecanismos moleculares subyacentes al reconocimiento del sustrato y la selectividad del sitio de desfosforilación.
Para identificar los determinantes de las interacciones enzima-sustrato.

Principales métodos:

Cristalografía de rayos X para determinar la estructura 3D del dominio de la 5-fosfatasa de SPsynaptojanin.
Análisis bioquímico del complejo enzima-ligando (Ca2+ y inositol (1,4)-bisfosfato).
Mutagénesis dirigida al sitio para sondear la especificidad del sustrato.

Principales resultados:

La estructura de resolución de 1,8 Å reveló un pliegue similar a las nucleasas dependientes de Mg2+, con un par catalítico His-Asp.
Se identificaron bucles específicos para la unión al polifosfato de inositol.
La orientación del inositol (1,4)-bisfosfato aclaró la selectividad del sitio de desfosforilación de la enzima.

Conclusiones:

La estructura determinada proporciona información sobre el mecanismo catalítico de las inositol polifosfato 5-fosfatasas.
La comprensión de los mecanismos de reconocimiento de sustratos puede informar estrategias para dirigir las enzimas en contextos de enfermedades.
Los estudios de mutagenesis identificaron residuos clave que rigen la especificidad del sustrato.

Más Videos Relacionados

PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions

PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions

Published on: July 27, 2017

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry

Published on: July 26, 2019

Videos de Conceptos Relacionados

Phosphorylation

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...

Protein Kinases and Phosphatases

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...

Phosphoinositides and PIPs

Phosphoinositides and PIPs

Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...

Mechanism of Filopodia Formation

Mechanism of Filopodia Formation

Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...

IP3/DAG Signaling Pathway

IP3/DAG Signaling Pathway

Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and...